In the next years to come one of the untapped natural energy sources will be made mainly by heavy crude oil; this implies that the petroleum industry will require more efficient secondary and tertiary recovery processes, thus this concept fuels the development and application of new alternatives for increasing the productivity by production site as well as development of new methods for improving the transport of the heavy crudes to refining centers. These aspects are relevant aspects in the oil industry, both for maintaining acceptable levels of production to meet the commitments of refining and hydrocarbons exports. However, heavy crude oil deposits are difficult to exploit, because of the high resistance to flow (i.e., high viscosity) and poor performance of distillable fraction (i.e., <538° C.); in addition, there exist price penalties for high concentration of contaminants and moisture, which reduce the profit margins.
Currently, there are some technologies that are used to improve the quality of the heavy and extra-heavy crudes within the production site, with the purpose of increasing the recovery factor; among the most important are steam the injection, cyclic steam injection, aquatermolysis, drained of steam by assisted gravity (SAGD), air injection, Toe-to-Heel Air Injection (THAI), conventional in-situ combustion and combustion in situ through intelligent wells. On the other hand, conventional crudes, i.e., with 20 to 32° API, are extracted from the production site by artificial systems of production, sometimes using primary and secondary recovery methods. However, in the case of the heavy crudes, i.e., with about 10-15° API, its extraction is complex, even more the improvement of their recovery factor, by using conventional techniques currently in application; thus, the use of more complex schemes are the logical choice, especially for increasing the recovery factor and to comply the crude quality requirements required in the exportation contracts, in the medium and long term.
However, the current technologies present serious limitations. For example, In the case of the steam injection assisted by gravity drainage (SAGD) and the cyclic steam stimulation processes (CSS), these can be applied only to shallow formations, i.e., no more than 1,000 m. All the air-injection technologies present the disadvantage of higher risks, because the injection of air starts an ignition fire in the site, which provokes a combustion front that moves from the injector well to the producer well, usually; however, during this process there are serious explosion risks, as well as the risk of diversion of the combustion front, which may extinguish the flame of the front of combustion before reaching the hydrocarbons deposit.
The THAI/CAPRI technology uses a vertical injection well that is combined with a horizontal production well, instead of only vertical wells. Thus, it consists of lighting a fire on-site, which is fed along with air from the well surface, by means of a vertical shaft. The air pressure makes it that the combustion chamber grows and develops a great amount of heat in the site. The heat reduces the viscosity of the heavy crude, which tends to flow easy towards a horizontal production well. The gas produced from the combustion pushes some crude oil fraction up to the surface.
The THAI process combines a special configuration of vertical and horizontal well with combustion in situ. CAPRI means that a catalyst is added to the gravel filling around the production well. The idea that underpins THAI/CAPRI is to start an underground fire as explained above, thus creating bitumen flow and, at the same time, improve the crude oil API gravity, before it leaves the ground.
Data from some patents related to the matter of improvement of both physical and chemical properties of heavy oils, with type of catalyst and precursors used for, are provided here below.
U.S. Pat. No. 7,001,504 refers to the use of a ionic composition in liquid phase, for the extraction of organic sulfur compounds that can be extracted by direct or partial oxidation of the sulfur compounds to sulfoxides or sulfones, in order to increase its solubility in the liquid phase Ionic composition and not, as in the present invention, using a liquid phase ionic catalyst in the presence of hydrogen, which intends to promote hydrocracking and hydrogenation type reactions.
U.S. Pat. No. 6,969,693 refers to the use of liquid phase ionic composition which is immobilized on a support for preparing a catalyst for promoting Friedel Crafts type reactions, especially for alkylation reactions, in contrast with the present invention that proposes the use of a liquid phase ionic composition catalyst in a highly dispersed form to promote hydrocarbons reactions of hydrocracking and hydrogenation.
U.S. Pat. No. 5,731,101 refers to the use of liquid phase ionic composition formed by metal halide and hydro-halogen-alkyl-amine, for the production of linear alkylbenzene, in contrast with the present invention that proposes the use of a liquid phase ionic composition catalyst in a highly dispersed form, which is iron-free, to promote hydrocarbons reactions of hydrocracking and hydrogenation.
U.S. Pat. No. 6,139,723 refers to use of liquid phase ionic composition based on certain assumptions for its application in bitumen and waste.
U.S. Pat. No. 4,136,013 refers to a catalyst in a homogenized suspension of Fe, Ti, Ni and V for crude oil and residue hydrogenation reactions.
U.S. Pat. No. 4,077,867 and U.S. Pat. No. 4,134,825 refers to the hydroconversion of coke and heavy crude oil with catalysts based on Mo naphthenates, which is not the main scope of present invention.
U.S. Pat. No. 4,486,293 used a catalyst in combination with a metal Group VI B or group B VIII from organic salts of these metals for applying in to the liquefaction of Coke, together with a hydrogen donor salt in aqueous solution. However, the catalyst is firstly soaked in coke prior to the liquefaction reaction, and it does not proceed with the liquid phase ionic composition catalyst prepared with inorganic salts of iron and molybdenum, which are dispersed in the crude oil and are not impregnated.
U.S. Pat. No. 5,168,088 refers to the use of a catalyst in slurry fluid for the liquefaction of coke through the precipitation of iron oxide in the matrix of Coke; it differs from liquid phase Ionic catalyst composition prepared on the basis of inorganic salts of iron and molybdenum that are dispersed in the oil and which do not precipitate.